Re: recursive function returning "setof"
От | Christopher Kings-Lynne |
---|---|
Тема | Re: recursive function returning "setof" |
Дата | |
Msg-id | 00a401c24798$7cc43630$0200a8c0@SOL обсуждение исходный текст |
Ответ на | recursive function returning "setof" (Fritz Lehmann-Grube <lehmannf@math.TU-Berlin.DE>) |
Список | pgsql-sql |
http://www3.us.postgresql.org/users-lounge/docs/7.2/postgres/plpgsql-control -structures.html Chris ----- Original Message ----- From: "Fritz Lehmann-Grube" <lehmannf@math.TU-Berlin.DE> To: "Christopher Kings-Lynne" <chriskl@familyhealth.com.au> Cc: <pgsql-sql@postgresql.org> Sent: Monday, August 19, 2002 11:22 PM Subject: Re: [SQL] recursive function returning "setof" > > Thanx Chris, > > but I can't find it. > My Programmer's Guide (.../pgsql/doc/html/xfunc-sql.html) says > > "12.2. Query Language (SQL) Functions > SQL functions execute an arbitrary list of SQL statements," > > Nothing about control structures in SQL functions additional to the normal > command-line syntax. Where can I find it ? > > and (.../pgsql/doc/html/plpgsql.html#PLPGSQL-ADVANTAGES) > > "23.1.1.1. Better Performance > SQL is the language PostgreSQL (and most other Relational Databases) use as > query language. It's portable and easy to learn. But every SQL statement > must be executed individually by the database server. > > That means that your client application must send each query to the database > server, wait for it to process it, receive the results, do some computation, > then send other queries to the server." > > Isn't it just the thing in plpgsql to add control structures to SQL ? > > Fritz > > Christopher Kings-Lynne wrote: > >>The problem is: > >>A SQL-Function cannot be recursive because it cannot call itself, and it > > > > can > > > >>perform no loops. > >>A PLPGSQL-Function cannot return sets. > > > > > > It can perform loops. Check the manual- you can do FOR and WHILE loops. > > 7.3 will be able to return sets from PLPGSQL funcs it seems. > > > > Chris > > > > > > > > ---------------------------(end of broadcast)--------------------------- > > TIP 4: Don't 'kill -9' the postmaster > > > > > > > ---------------------------(end of broadcast)--------------------------- > TIP 3: if posting/reading through Usenet, please send an appropriate > subscribe-nomail command to majordomo@postgresql.org so that your > message can get through to the mailing list cleanly >
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